The University of Kansas is coming under fire from a free-speech watchdog group for suspending a journalism professor over his controversial tweets about the National Rifle Association.

David Guth, an associate professor of journalism, was put on indefinite administrative leave on Friday for implying on Twitter that he wished violent harm upon the families of the NRA.

Hours after last week’s Washington Navy Yard rampage, the professor reportedly tweeted: “#NavyYardShooting The blood is on the hands of the #NRA. Next time, let it be YOUR sons and daughters. Shame on you. May God damn you.”

A spokesman for the NRA called Mr. Guth’s remarks “disgusting” hate speech and called for his firing. By the week’s end, the chancellor of the public university had ordered his suspension “in order to prevent disruptions to the learning environment for students.”

The Foundation for Individual Rights in Education, a Philadelphia-based group that advocates for free speech on college campuses, came to Mr. Guth’s defense in a letter emailed to the chancellor on Sunday.

“While KU is free to speak out against Guth’s comments, it may not, consistent with its moral and legal obligations under the First Amendment, punish him for expressing his views,” FIRE’s letter said.

The letter goes on to say that the university “risks dramatically chilling the free expression of all members of the KU community by allowing any impression to persist that his speech did not merit the First Amendment’s protection.”

Mr. Guth declined comment. He told the Associated Press earlier that the university’s move was “painful” for him but agreed to take an earlier than planned sabbatical to allow “some time for cooler heads to prevail.” He also blamed the NRA for waging “an unrelenting campaign of harassment” against him.

A Kansas University spokeswoman declined to comment on FIRE’s letter and reiterated that Mr. Guth wasn’t on any kind of sabbatical but on administrative leave.

As Law Blog mentioned earlier, the Supreme Court has said that the government may not punish public employees who speak out “as citizens about matters of public concern,” with some exceptions.

“So long as employees are speaking as citizens about matters of public concern, they must face only those speech restrictions that are necessary for their employers to operate efficiently and effectively,” the high court ruled in 2006.

“I don’t think a university could claim that their interest in efficient operations justifies punishing a professor for speech protected by the First Amendment,” Will Creeley, FIRE’s director of legal and public advocacy, told Law Blog.

Public university professors may have additional protections in their labor contracts.

The constitutional protections though don’t encompass unprotected forms of speech, like incitement or harassment. But FIRE officials think the professor’s comments can’t be construed as either one. Incitement, it notes, must be intended and likely to produce “imminent lawless action.”

After last year’s Newtown, Conn., school massacre, University of Rhode Island professor Erik Loomis was the center of a similar controversy after he tweeted that he wanted “Wayne LaPierre’s head on a stick,” referring to the NRA leader.

The president of the University of Rhode Island, David M. Dooley condemned the professor’s remarks, saying the university doesn’t condone “threats of violence.”

Some academics criticized the university for not defending Mr. Loomis’s speech rights. The university’s president then clarified that the professor’s personal remarks were protected by the First Amendment “however intemperate and inflammatory they may be.”

About Law Blog

The Law Blog covers the legal arena’s hot cases, emerging trends and big personalities. It’s brought to you by lead writer Jacob Gershman with contributions from across The Wall Street Journal’s staff. Jacob comes here after more than half a decade covering the bare-knuckle politics of New York State. His inside-the-room reporting left him steeped in legal and regulatory issues that continue to grab headlines.

A federal judge in Manhattan rejected a bid by the conservative advocacy group Citizens United to stop New York Attorney General Eric Schneiderman from requiring that charities disclose to him their major donors.

Concerns about a gender gap in the legal profession tend to focus on issues like pay, billing rates and who makes partner. A new study by the American Bar Association looks inside the federal courtroom to see who's trying cases.